Mercruiser 5.7 Running hot

[fg2matt]

The last couple times I took my boat out the temp was around 170-180 on my 5.7L mercruiser. Is that too hot, or is that normal? Oil pressure is good, at around 80 psi. Could this be a sending unit problem? How can I check the temp other than what the gauge is telling me?

Thanks

 

[Don S]

Re: Mercruiser 5.7 Running hot

The last couple times I took my boat out the temp was around 170-180 on my 5.7L mercruiser. Is that too hot, or is that normal?

If that is higher that what it normally runs, then yes you have a problem. A raw water cooled boat should not see 180?

When was the last time the impeller was replaced?

 

[fg2matt]

Re: Mercruiser 5.7 Running hot

June of 2011. I'm guessing this needs to be replaced annually, so where could I pick one up for cheap? Alpha One Gen 1

 

[fg2matt]

Re: Mercruiser 5.7 Running hot

And I have no idea what it's supposed to run, as I've only owned the boat for less than a year and I've only had it out twice.

 

[Don S]

Re: Mercruiser 5.7 Running hot

The way you worded it (The last couple times I took my boat out ) it sounded like you have run it many times and just the last couple times it was running different.
But since you aren't sure, get a temp gun and check right at the base of the sender on the engine and see if it matches the gauge.

Every other year on Alpha impellers is a rule of thumb I go by.

 

[fg2matt]

Re: Mercruiser 5.7 Running hot

Ok, I'll probably replace it just because it will need it soon. Also, do the bellows and such need to be replaced at the same time?

I was thinking about getting these. Is that a good idea?

Mercruiser Alpha One Gen 1 Water Pump from MercAftermarkets

Mercruiser Alpha One Gen 1 Transom Repair Kit

And the anodes are shot, so this as well

Mercruiser Alpha One Gen 1 Anode Kit

Are these parts ok to run on the outdrive? Is SEI any good?

Sorry, I'm a bit of a noob

Thank you so much for all your help!

 

[Don S]

Re: Mercruiser 5.7 Running hot

Since you come to iboats to get repair information, why don't you click on the Merc Parts icon above your post and buy your parts from iboats. That's how they pay for this forum.

 

[fg2matt]

Re: Mercruiser 5.7 Running hot

Oh wow, Didn't even notice that! Alright so what all do I need? the bellows were replaced in 2011, do they need to be replaced as well?

Would this one work?

Water Pump Kit - Sierra - iboats

Should I get the complete one or the mallory one? Is the only difference Sierra vs Mallory?



The boat will be getting a new transom soon so when the guy takes the outdrive off will he need the "Transom Seal Kit" To re-install it?

 

[Don S]

Re: Mercruiser 5.7 Running hot

That will work, but do you really need the whole thing? Usually just the impeller kit will do the job unless there has been an overheat and melted the pump housing. Lots cheaper as well.
Water Pump Kit - Sierra - iboats

 

[Don S]

Re: Mercruiser 5.7 Running hot

The boat will be getting a new transom soon so when the guy takes the outdrive off will he need the "Transom Seal Kit" To re-install it?

Unless he is going to disassemble the gimbal housing to replace the bellows he won't need the kit. What he will need is the big oring seal around the outer edge of the gimbal housing, and the seal rings for the exhaust Y.

What year, or better yet, the Merc serial number of your engine.


You need parts 31 and 13 for sure.

 

[fg2matt]

Re: Mercruiser 5.7 Running hot

ok cool, yeah the boat ran great even at 180 degrees, so I doubt anything is melted, and I had good water flow. So I will just get what you recommend.

 

[fg2matt]

Re: Mercruiser 5.7 Running hot

It is an '89 Merc 5.7 350, I dont have the serial number right now I'm at work.

 

[Don S]

Re: Mercruiser 5.7 Running hot

You won't need the seal kit if it's only 2 years old. I edited my last reply with the parts he will need.

 

[fg2matt]

Re: Mercruiser 5.7 Running hot

Alright cool, thank you so much!